Sugar cane harvesting or cut operations require a certain degree of precision for good crop yield. Ideally, the cut height should be at a level substantially close to the surface of the ground so as to harvest the optimal crop without damage to the equipment and at minimal cost.
If the harvest cut is made above the ideal cut height, the higher than desirable cut will result in harvest losses in the form of unharvested raw material, perhaps occasioning the need for an additional harvesting cut to try to try to recover the remaining unharvested raw material, with additional expenditures of time and additional wear and tear upon the harvesting equipment, or the loss of revenue from the unharvested raw material.
If the harvest cut is made below the ideal cut height, various, other, undesirable consequences may result. A harvest cut below the ideal height will not only result in increased damage to the plant, thereby decreasing the long term productivity of the cane plantation, but also in higher mineral levels in the harvested cane, and will cause increased damage to the base cutter knives, resulting in accelerated wear of such knives due to the constant wear against the soil. Such wear against the soil reduces productivity due to the need for more frequent stoppages of the machine for maintenance and for knife changes into fixed or floating base cutter units, and also results in higher motor and energy costs and greater waste since the equipment is required to operate in adverse or less than desirable conditions.
In light of these factors, it has long been recognized that it would be highly desirable and beneficial if harvesting machines could be provided with height adjustment means for the base cutter units that would allow the base cutter units to be moved vertically as ground irregularities are encountered during the course of the harvesting operation since such adjustability would allow both better regularization of the cut height of the raw material and a reduction in the pressure peaks associated with the cutting apparatus that would otherwise occur due to non-optimal cutting conditions. It has also been considered desirable that, in order to obtain an appropriate cut operation, while the height of the cutter disk should be adjustable, the same cut angle should be maintained regardless of the operational height.
Consequently, in view of the recognized desirability of maintaining the base cutter at a constant base cutter angle, of minimizing the undesirable index of cane escape in relation to the feed rollers, of obviating losses due to cane that drops to the soil and is not picked up by the cane harvester, and of avoiding high indices of minerals in the raw material processed by the cane harvester, various efforts to provide improved harvesting equipment have been undertaken, as a result of which various constructions have been developed.
One type of construction that has been developed employs cutter disks that are articulatedly connected to the machine chassis by means of arms in pantographic arrangement. In this type of construction, the base cutter unit is fixed to the chassis of the machine in such a way that it can be moved vertically to provide a degree of height adjustment for the disks and knives. Such type of construction has found wide use and is typical of the type of harvesting machines that employ vertically adjustable base cutter units fixed to the chassis.
One known construction of this type also includes an elevation system that can function to support all the mobile portions of the chassis as well as the base cutter unit and that is operable by the machine's operator to effect vertical movements of the base cutter unit. With this system, an operator actively controls the height of the fixed base cutter unit by operating controls to elevate or lower the unit, and, during harvesting operations, the operator attempts to monitor soil irregularities and to adjust the height of the base cutter unit accordingly so that the operating height of the cutter disk will track the soil irregularities. However, even a good operator's ability to accurately monitor and track soil irregularities, especially over an extended period of time and from a vantage point distanced to some degree from the cutting knives, is limited, and soil and other environmental conditions can compound the difficulties. Especially if the soil is not well prepared, it is difficult for the operator to accurately adjust, in an ongoing manner, the height of the cutting knives so as to, on the one hand, avoid raw material losses, generally of the richest portion of the plant, yet, on the other hand, avoid premature wear of the base cutter knives and minimize the feeding of minerals.
Such a construction utilizing a base cutter unit fixed to the chassis has been employed in a great number of sugar cane harvesters, and has been further adapted whereby elevation of the base cutter unit may be controllable not only manually, but, in some instances and under some conditions, also by semi-manual and partially automated systems, including certain systems that are responsive to pressure detection and other systems that utilize ground tracking mechanisms or systems, especially systems that employ-mechanical or electro-mechanical implements and components. In some relatively recent constructions, ground tracking and the detection of surface irregularities has been addressed through the use of various sonic and electronic techniques instead of or in addition to mechanical implements.
Some attempts to solve the problems noted above have resulted in development of constructions that make use, at least to some extent, of self leveling systems for base cutter disks. In such types of constructions, the base cutter disk is often connected to the machine chassis through an articulation, with the cutter disk operating behind the articulation and being pulled towards the surface of the soil to follow the soil irregularities. In such known constructions, the base cutter unit utilizes a support system formed by articulated arms in a pantographic arrangement, and the base cutter unit can move, and oscillate, during a cutting operation, in a vertical sense, and over a certain width, to generally follow or track undulations of the land as the harvesting machine is operated. With such constructions, the base cutter unit may thus be described as a floating unit since it seemingly “floats” at or about a relatively uniform elevation above ground level, while maintaining generally constant its inclination angle in relation to the soil.
In one particular construction, a support system is provided for each cutter disk, and that support system includes a pair of generally longitudinally extending articulation arms connected to the harvesting machine, with one arm being an upper arm and the other arm being a lower arm, the opposite ends of which arms are connected, respectively, to the chassis of the machine and to the cutter unit. The articulation arms of such base cutter device are responsive to forces acting against the base cutter disk, due to effects of the sugar cane or the soil, to effect vertical movements of the base cutter device. If the cutter disk encounters an increased resistance to its operation and forward movement, as a function of an encountered obstacle, as, for example, a mound or higher elevation in the soil contour, an upward force is applied to the articulation arms, which applied force tends to cause the cutter unit to move vertically upward.
Harvesting machines of the various construction types may typically include an indicator system that can provide to the machine operator certain information regarding the base cutter position or displacement, including information as to the intensity and frequency of movement or oscillation of the cutter disks in upward or downward directions, and particularly information as to the resulting deviation relative to the work height for which the support system of the base cutter unit has been set up. In certain of the constructions, the indicator system comprises, primarily, a flexible cable, with one end of the cable connected to the base cutter unit and the other end being associated with an indicator pointer located in the operator's cabin. In other constructions, the indicator system may make use of two hydraulic cylinders of double action operation, with one being installed in the base cutter unit and the other being associated with an indicator pointer. With the latter type of indicator system, an operator, through hydraulic pistons, can set the height of the chassis to a desired level, adapted to the soil type to be worked, and can thus define and establish a desired working height for the base cutter unit when in a nominal position.
The latter type of indicator system has found use in a construction where, after the desired working height is established for a floating base cutter unit, the floating base cutter unit attempts to follow the ground track and the cutting unit deviates from its nominal position relative to the chassis when surface irregularities are encountered, moving up and down, to try to maintain the desired working height. The displacement indicator allows the operator to monitor the degree of vertical movement of the base cutter unit relative to the chassis. In practice, however, due to system design constraints and in order to prevent damage to the harvesting machine and its components, movement of the base cutter unit relative to the chassis is limited to some maximum such that, if a significant irregularity in the ground contour is encountered, excessive displacement of the base cutter unit relative to the chassis is blocked by a respective windowsill or movement limit that is generally associated with the machine chassis. Consequently, when ground irregularities that exceed the machine's design capabilities are encountered, the base cutter unit cannot be moved sufficiently to be able to properly track and follow the ground track irregularity and the desired work height cannot be maintained.
Because information as to the amount of movement of the base cutter unit relative to the chassis is being provided to the operator via the indicator system, such as by way of an indicator pointer viewable by the operator, the operator may, by closely monitoring the information, be able to take actions to manually adjust the chassis height when conditions so warrant. When a significant ground irregularity which effects a maximum movement of the base cutter unit is encountered and information is communicated to the operator by the indicator system, the operator can command appropriate adjustments so that the movement of the base cutter unit relative to the chassis can be brought back within movement allowances, thereby permitting the base cutter unit to be moved to a better working height and/or reducing damage or wear to the cutter unit due to ground contact. However, such adjustment in the chassis height also effects a change in the nominal work height as established by the height of the chassis, and, if a corrective readjustment is not thereafter made after the significant ground irregularity has been cleared, the working height for the cutting operation, though perhaps improved as the base cutter unit traversed the ground irregularity, may thereafter, when the base cutter unit has cleared the ground irregularity, be less than optimal. The operator must therefore be prepared to quickly readjust the position of the base cutter unit when the ground irregularity is cleared. Consequently, even with such a construction, the operator must be vigilant and attentive to the indicator system as well as to the overall soil conditions and must be proactively involved in making adjustments during harvesting so as to try to maintain a desired average working height. In practice, the machine operator must typically be able to notice random ground irregularities that, while perhaps not generally severe, nonetheless effect movements, generally greater than about 60 mm., of the base cutter unit relative to the chassis, and he must be able to act quickly to elevate or lower the chassis so as to maintain the elevational positioning of the base cutter unit within the vertical movement window or range as determined by the windowsills of vertical movement, and to thereafter again quickly elevate or lower the chassis to return it to a more desirable height when the ground irregularity is cleared or other adjustment of the chassis height becomes necessary or desirable.
Although these various constructions and their systems have found broad application, the techniques of their operation still require that the operator be constantly attentive, and the base cutter efficiency remains highly dependent on the dexterity and vigilance of the operator. In light thereof, because of the frequency with which unexpected soil irregularities and intensities are encountered, and because of the degradation of responsiveness experienced by even the most skilled operators over the course of long operation periods, such well-known systems and their techniques have seldom been able to consistently achieve the efficiency desired.
With all of the noted systems and techniques, frequent and necessary adjustments in the height of the chassis are required by the operator in order to maintain the base cutter unit within its acceptable height window and to realize an optimal harvesting cut. However, even under ideal conditions and with well-rested and competent operators, the time delay between the operator's recognition that some corrective adjustment is desirable and his actions to effect the desired adjustment results in time periods during which the harvesting cut is less than ideal.
In addition, the existence of conditions which ideally would result in a recognition by the operator that some corrective adjustment is desirable is not always readily apparent or detectable by the operator. For example, if the ground surface includes a sudden elevation, but the soil is loose and not very resistant, when a cutter disk unit of a particular harvesting machine encounters such elevation, the weight of an under-central base cutter unit skate may be such that that elevation is not appropriately detected and that ground irregularity is not appropriately tracked and made evident to the operator. In such a situation, any vertical adjustment in the height of the base cutter relative to the chassis may be such that the upper movement limit is not reached and the movement indication provided to the operator shows the base cutter unit to still be within an acceptable height window. In such a situation, even though the cutter disk may be operating to an undesirable depth, and thereby demanding higher hydraulic pressure, the operator may be unaware of the condition.
While various constructions have been developed that have lessened to some extent the need for reliance upon manual adjustments, such as by employing height adjustment systems that are only semi-manual or which are partially automated to be responsive to certain monitored conditions, such as detected cutting pressure required or a detected ground surface irregularity, no known construction has heretofore employed a system for automatedly adjusting the height of the cutting apparatus to maintain an approximately desired cutting height without the need for constant and continuing operator attention and intervention.
One relatively recent development has recognized that, depending upon various conditions and circumstances, a machine operator may find it beneficial to be able to optionally select, and to be able to set the harvesting machine to selectively operate in, either a ground tracking mode, sometimes referred to as a stubble height mode, or in a pressure mode, and to vary the mode of operation as he determines appropriate for the circumstances. Although such a system affords certain advantages and provides the operator with greater flexibility in controlling the height of the cutting apparatus, each operating mode continues to suffer from the attendant disadvantages for that mode, and significant continuing operator attention and intervention remains necessary.
The present invention is intended to alleviate at least certain of the noted disadvantages and problems by providing a control system that can rely on both ground tracking information and cutting pressure information to automatedly adjustably control the chassis height, and the height of an associated base cutter unit, of a harvesting machine during a harvesting operation, and to thereby better effect a harvesting cut at an average cut height as predefined by the operator of the harvesting machine, with improved pressure maintenance, and without the need for continual user intervention to make adjustments for ground surface irregularities.
In addition, the present invention is intended to provide a control system that can be easily incorporated into many pre-existing harvesting machines and a manner and method of operation in accordance with which previous harvesting machines can be readily modified to operate without requiring significant alterations in the pre-existing machine controls and systems that are in use for adjusting chassis height.